contrib/bind-9.5.2/lib/bind/isc/ev_streams.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996-1999 by Internet Software Consortium
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* ev_streams.c - implement asynch stream file IO for the eventlib
  19  * vix 04mar96 [initial]
  20  */
  21
  22 #if !defined(LINT) && !defined(CODECENTER)
  23 static const char rcsid[] = "$Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp $";
  24 #endif
  25
  26 #include "port_before.h"
  27 #ifndef _LIBC
  28 #include "fd_setsize.h"
  29 #endif
  30
  31 #include <sys/types.h>
  32 #include <sys/uio.h>
  33
  34 #include <errno.h>
  35
  36 #include "isc/eventlib.h"
  37 #ifndef _LIBC
  38 #include <isc/assertions.h>
  39 #endif
  40 #include "eventlib_p.h"
  41
  42 #include "port_after.h"
  43
  44 #ifndef _LIBC
  45 static int      copyvec(evStream *str, const struct iovec *iov, int iocnt);
  46 static void     consume(evStream *str, size_t bytes);
  47 static void     done(evContext opaqueCtx, evStream *str);
  48 static void     writable(evContext opaqueCtx, void *uap, int fd, int evmask);
  49 static void     readable(evContext opaqueCtx, void *uap, int fd, int evmask);
  50 #endif
  51
  52 struct iovec
  53 evConsIovec(void *buf, size_t cnt) {
  54         struct iovec ret;
  55
  56         memset(&ret, 0xf5, sizeof ret);
  57         ret.iov_base = buf;
  58         ret.iov_len = cnt;
  59         return (ret);
  60 }
  61
  62 #ifndef _LIBC
  63 int
  64 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
  65         evStreamFunc func, void *uap, evStreamID *id)
  66 {
  67         evContext_p *ctx = opaqueCtx.opaque;
  68         evStream *new;
  69         int save;
  70
  71         OKNEW(new);
  72         new->func = func;
  73         new->uap = uap;
  74         new->fd = fd;
  75         new->flags = 0;
  76         if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
  77                 goto free;
  78         if (copyvec(new, iov, iocnt) < 0)
  79                 goto free;
  80         new->prevDone = NULL;
  81         new->nextDone = NULL;
  82         if (ctx->streams != NULL)
  83                 ctx->streams->prev = new;
  84         new->prev = NULL;
  85         new->next = ctx->streams;
  86         ctx->streams = new;
  87         if (id != NULL)
  88                 id->opaque = new;
  89         return (0);
  90  free:
  91         save = errno;
  92         FREE(new);
  93         errno = save;
  94         return (-1);
  95 }
  96
  97 int
  98 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
  99        evStreamFunc func, void *uap, evStreamID *id)
 100 {
 101         evContext_p *ctx = opaqueCtx.opaque;
 102         evStream *new;
 103         int save;
 104
 105         OKNEW(new);
 106         new->func = func;
 107         new->uap = uap;
 108         new->fd = fd;
 109         new->flags = 0;
 110         if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
 111                 goto free;
 112         if (copyvec(new, iov, iocnt) < 0)
 113                 goto free;
 114         new->prevDone = NULL;
 115         new->nextDone = NULL;
 116         if (ctx->streams != NULL)
 117                 ctx->streams->prev = new;
 118         new->prev = NULL;
 119         new->next = ctx->streams;
 120         ctx->streams = new;
 121         if (id)
 122                 id->opaque = new;
 123         return (0);
 124  free:
 125         save = errno;
 126         FREE(new);
 127         errno = save;
 128         return (-1);
 129 }
 130
 131 int
 132 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
 133         evStream *str = id.opaque;
 134
 135         UNUSED(opaqueCtx);
 136
 137         str->timer = timer;
 138         str->flags |= EV_STR_TIMEROK;
 139         return (0);
 140 }
 141
 142 int
 143 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
 144         evStream *str = id.opaque;
 145
 146         UNUSED(opaqueCtx);
 147
 148         str->flags &= ~EV_STR_TIMEROK;
 149         return (0);
 150 }
 151
 152 int
 153 evCancelRW(evContext opaqueCtx, evStreamID id) {
 154         evContext_p *ctx = opaqueCtx.opaque;
 155         evStream *old = id.opaque;
 156
 157         /*
 158          * The streams list is doubly threaded.  First, there's ctx->streams
 159          * that's used by evDestroy() to find and cancel all streams.  Second,
 160          * there's ctx->strDone (head) and ctx->strLast (tail) which thread
 161          * through the potentially smaller number of "IO completed" streams,
 162          * used in evGetNext() to avoid scanning the entire list.
 163          */
 164
 165         /* Unlink from ctx->streams. */
 166         if (old->prev != NULL)
 167                 old->prev->next = old->next;
 168         else
 169                 ctx->streams = old->next;
 170         if (old->next != NULL)
 171                 old->next->prev = old->prev;
 172
 173         /*
 174          * If 'old' is on the ctx->strDone list, remove it.  Update
 175          * ctx->strLast if necessary.
 176          */
 177         if (old->prevDone == NULL && old->nextDone == NULL) {
 178                 /*
 179                  * Either 'old' is the only item on the done list, or it's
 180                  * not on the done list.  If the former, then we unlink it
 181                  * from the list.  If the latter, we leave the list alone.
 182                  */
 183                 if (ctx->strDone == old) {
 184                         ctx->strDone = NULL;
 185                         ctx->strLast = NULL;
 186                 }
 187         } else {
 188                 if (old->prevDone != NULL)
 189                         old->prevDone->nextDone = old->nextDone;
 190                 else
 191                         ctx->strDone = old->nextDone;
 192                 if (old->nextDone != NULL)
 193                         old->nextDone->prevDone = old->prevDone;
 194                 else
 195                         ctx->strLast = old->prevDone;
 196         }
 197
 198         /* Deallocate the stream. */
 199         if (old->file.opaque)
 200                 evDeselectFD(opaqueCtx, old->file);
 201         memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
 202         FREE(old);
 203         return (0);
 204 }
 205
 206 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
 207 static int
 208 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
 209         int i;
 210
 211         str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
 212         if (str->iovOrig == NULL) {
 213                 errno = ENOMEM;
 214                 return (-1);
 215         }
 216         str->ioTotal = 0;
 217         for (i = 0; i < iocnt; i++) {
 218                 str->iovOrig[i] = iov[i];
 219                 str->ioTotal += iov[i].iov_len;
 220         }
 221         str->iovOrigCount = iocnt;
 222         str->iovCur = str->iovOrig;
 223         str->iovCurCount = str->iovOrigCount;
 224         str->ioDone = 0;
 225         return (0);
 226 }
 227
 228 /* Pull off or truncate lead iovec(s). */
 229 static void
 230 consume(evStream *str, size_t bytes) {
 231         while (bytes > 0U) {
 232                 if (bytes < (size_t)str->iovCur->iov_len) {
 233                         str->iovCur->iov_len -= bytes;
 234                         str->iovCur->iov_base = (void *)
 235                                 ((u_char *)str->iovCur->iov_base + bytes);
 236                         str->ioDone += bytes;
 237                         bytes = 0;
 238                 } else {
 239                         bytes -= str->iovCur->iov_len;
 240                         str->ioDone += str->iovCur->iov_len;
 241                         str->iovCur++;
 242                         str->iovCurCount--;
 243                 }
 244         }
 245 }
 246
 247 /* Add a stream to Done list and deselect the FD. */
 248 static void
 249 done(evContext opaqueCtx, evStream *str) {
 250         evContext_p *ctx = opaqueCtx.opaque;
 251
 252         if (ctx->strLast != NULL) {
 253                 str->prevDone = ctx->strLast;
 254                 ctx->strLast->nextDone = str;
 255                 ctx->strLast = str;
 256         } else {
 257                 INSIST(ctx->strDone == NULL);
 258                 ctx->strDone = ctx->strLast = str;
 259         }
 260         evDeselectFD(opaqueCtx, str->file);
 261         str->file.opaque = NULL;
 262         /* evDrop() will call evCancelRW() on us. */
 263 }
 264
 265 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
 266 static void
 267 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
 268         evStream *str = uap;
 269         int bytes;
 270
 271         UNUSED(evmask);
 272
 273         bytes = writev(fd, str->iovCur, str->iovCurCount);
 274         if (bytes > 0) {
 275                 if ((str->flags & EV_STR_TIMEROK) != 0)
 276                         evTouchIdleTimer(opaqueCtx, str->timer);
 277                 consume(str, bytes);
 278         } else {
 279                 if (bytes < 0 && errno != EINTR) {
 280                         str->ioDone = -1;
 281                         str->ioErrno = errno;
 282                 }
 283         }
 284         if (str->ioDone == -1 || str->ioDone == str->ioTotal)
 285                 done(opaqueCtx, str);
 286 }
 287
 288 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
 289 static void
 290 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
 291         evStream *str = uap;
 292         int bytes;
 293
 294         UNUSED(evmask);
 295
 296         bytes = readv(fd, str->iovCur, str->iovCurCount);
 297         if (bytes > 0) {
 298                 if ((str->flags & EV_STR_TIMEROK) != 0)
 299                         evTouchIdleTimer(opaqueCtx, str->timer);
 300                 consume(str, bytes);
 301         } else {
 302                 if (bytes == 0)
 303                         str->ioDone = 0;
 304                 else {
 305                         if (errno != EINTR) {
 306                                 str->ioDone = -1;
 307                                 str->ioErrno = errno;
 308                         }
 309                 }
 310         }
 311         if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
 312                 done(opaqueCtx, str);
 313 }
 314 #endif /* !_LIBC */
 315
 316 /*! \file */